Apparatus for making propellers



S. HEATH.

APPARATUS FOR MAKING PROPELLERS. APPLICATION FILED MAY 16, 1918.

1 ,364, 1 96. Patented Jan. 4, 1921.

Pitt TENT l FICE.

APPARATUS FOR MAKING PBOPELLERS.

Application filed May 16, 1918.

To all whom 2'23 may concern:

Be it known that I, Srnnonn I'IEATI-I, a citizen of the United Eltates,residing at Baltimore, State of Maryland, have invented new and usefulImprovements in Apparatus for lllaking Propellers, of which thefollowing is a specification.

My inventionrelates to the making of propellers, particularly the woodenpropellers designed and constructed for aerial propulsion, and itrelates especially to apparatus for use in outlining a propeller blankor propeller or the step of outlining in the gen oral apparatus andmethod of making such propellers.

Owing to the nature of the material of which these propellers areconstructed, it is diificult to successfully cut the various parts tothe exact desired shape, and it is also ditlicult to properly hold thework while being operated upon. A suitable blank is first made,preferably by gluing together laminations of wood or other suitablematerial. These laminations are of the general shape of the propeller,and the blank so constructed has roughly the general form desired forthe finished article, which is produced by cutting the blank down to theexact outline and shape of blades and hub desired.

@n account of the greater strength of the various parts of the blank,while in the rough I prefer to cut the work to the exact outline beforethe faces of the blades are worked down to the final shape, therebyreducing the chance of splitting or breaking to a minimum, although myapparatus and method are operative in another sequence of operations.

The invention resides principally in the mounting and holding of thework in such a manner that the propeller as a whole will be accuratelycentered and the two or more blades will be correctly outlined so thatthe structure as a whole will embody that peculiar relation of theparts, that nicety of balance, and that equality oi function which arenecessary for the successful operation of an aerial propeller.

Apparatus for carrying the invention into effect is illustrated in theaccompanying drawings, in which Figure l is a perspective view ofapparatus for outlining a propeller or propeller blank, said apparatusincluding the pattern Specification of Letters Patent.

Patented Jan. 4:, 1921.

Serial No. 234,960.

and propeller or blank, a three-bladed propeller being shown;

Fig. 2 is an edge View of the pattern and propeller blank on an enlargedscale, the parts including the end supporting and fastening devicesbeing shown displaced from their operative positions;

Fig. 3 is a sectional view on a greatly enlarged scale, showing the hubcentering and mounting portion of the pattern and blank;

Fig. 4 is an enlarged View of one of the supporting and fasteningdevices; and

Fig. 5 is a similar View of a modified form ot' said suporting andfastening device.

Referring to the drawings, 10 indicates the pattern which is preferablyof wood or other suitable material and which has the contour which it isdesired to give to the finished propeller. The pattern is adapted torest upon a table ll provided with cu ters 12 adapted to outline theedge of the propeller or the propeller blank in accordance with thepattern, immediately below the cutters being provided a smoothnonrotating follower member 13 for engagement with the pattern.

Each pattern is provided with a hub portion 14 and a plurality of bladeportions 15, three of which latter are shown in the drawings, althoughany other desired number may be provided according to the style ofpropeller under construction.

At the hub portion, the pattern 10 is pr0- vided with means forcentering the work upon the pattern, this means being shown as a pin 16mounted in a suitable socket l7 and extending upwardly the properdistance to permit of the application of nut 18 or other fastening meansalter the work has been put in place. Surrounding the pin 16 ispreferably employed a sleeve 19 adapted to fit snugly within the centralbore of the hub portion 20 of the propeller or propeller blank 21. Thiscentral perforation in the propeller blank accurately centers the blankupon the pattern, and as the pattern has been accurately cut to providethe exact length and shape of each blade, the propeller will be evenlybalanced for accurate revolution.

Each blade portion 22 of the propeller blank is supported upon thepattern by a suitable combined holding and supporting device 23, oneform of which is shown in Figs. 2 and 4:. This form consists of a socketor bushing 24 suitably mounted near the outer end of each of the bladeportions of the pattern, and the under surface of the pattern ischambered at 25 beneath this bushing. A sleeve 26} has a slidingengagement with the bushing and extends through a perforation in thepattern. The upper end of this sleeve 26 is provided with sharpenedprojections or tines 27 for engagement with the propeller blank and thelower end of said sleeve is split as shown at 28 for a distunes from thelower end. The extreme lower end the sleeve 26 is provided with inclineds rfaces which are engaged by a locking member 29 having at its upperend a threaded portion 30 to be screwed into the propeller blank, and atits lower end a handle or other turning means 31 and a conical surface32 for engagement with the inclined surface of the sleeve 26.

In the production of a propeller, the blank is preferably built up oflaminations shown in Figs. 2 to 5, these laminations overlapping toprovide the general form of the propeller. A central aperture isprovided, and the blank is centered upon the pattern by slipping theblank upon the sleeve 19 which snugly fits the central perforation andaccurately centers the blank upon the pattern. After securing the blankin place by means of nut 18 or any other suitable device, the bladeportions 22 are supported and secures after they have been brought intoproper position over the blas portions of the pattern, by slipping thelooking sleeve 26 and pin 29 up through the socket 24 until the threadedportion of the locking pin 30 engages the blank when it may be screwedinto the blank by turning the end 81. The parts are so proportioned thatwhen the threaded portion 86 of the locking pin has taken a firm hold ofthe blank, the cone surface 32 engages the lower inclined or conicalsurface of split sleeve 26, when continued upward movement of thelocking pin 29 spreads the split portion of the sleeve 26 sufficientlyto securely lock the entire device. At the same time that this upwardlocking pressure of the cone surface is exerted, the sleeve 26 is pushedupward to a certain extent to cause the tines 27 also to engage theblank. The combined action is therefore that the sleeve 26 is preventedfrom turning by its engagement with the blank and is then lookedsecurely in the adjusted position. locking are therefore substantiallyautomatic, and the blade portion of the blank is both supported and heldin the proper position.

In place of the automatic adjusting and locking device shown in Fig. 4:,I may employ a more simple arrangement such as shown in Fig. 5, in whicha locking pin 33 is mounted in the socket 24 and is provided Theadjustment and incense with a threaded portion 34 at its upper end. Thispin is secured in its adjusted position by means of a set-screw 35.

After the propeller has been securely mounted on the pattern, as aboveindicated, the combination as a whole may be slid around and manipulatedupon the table 11 so as to bring all of the pattern into engage mentwith the smooth portion 13 of the cutters, in order to accurately cutthe edge or outline of all parts of the blank. After the blank has beentreated in this way, it is removed from the pattern and the faces of thehub and blade portions are finished in any suitable or known manner,thus completing the method of construction.

An important function of the described method of outlining aeroplanepropellers of two, three, four, or any number of blades is that bythedescribed means, after having bored the center hole in the roughpropeller block thereby establishing its precise geometrical center, itis possible by means of an accurately made follower pattern to out linethe blades with perfect geometric accuracy as regards not only theiruniformity of size and shape but the precise and accurate space of theblades equidistant from each other. This eliminates the very tedious andexpensive process of trameling the blades for spacing them and foraccurately locating outlining patterns for marking off their contourbefore reducing them to size by hand-cutting or other method previouslyemployed.

A further important feature relates to the spur holders near theextremities of the blades. These are so made that at the same time thespur is inserted in the propeller block or immediately thereafter, theheight of the spur is adjusted to accommodate the correct relationbetween the outline blank and the propeller block. Without thisprovision for vertical adjustment the outline blank would in most casesbe distorted either by drawing its ends up toward the propeller block orby pushing them away from it. Any distortion of the outline blank inthis measure would prevent the said blank from lying flat upon the table11 of the machine and permit it to rock to and from the cutters 12 insuch a way as to prevent accurate and uniform work.

While I have shown and described one form of apparatus for carrying myinvention into efiect, it is understood that many modifications may bemade without departing from the invention, and all such modifications,ll consider within the scope and purview of the invention and aim tocover by the appended claims.

I claim 1. In apparatus for making propellers, an outline pattern havingthe peripheral contour desired for the propeller, means carried neeaneeby said pattern for centering a propeller or propeller blank upon saidpattern comprising a shaft adapted to extend through a central hole inthe hub portion of the propeller blank and having fastening means forclamping said propeller blank on said pattern, a combined supporting andholding device carried by said pattern for supporting in fixed positioneach blade portion of the work upon the pattern, a table upon which saidpattern rests and is capable 01" sliding, a cutter on said table, androtatably mounted on an axis parallel to the central bore of thepropeller blank for cutting the edge of the work, and a smooth surfaceassociated with said cutter for contact with said pattern.

2. ln apparatus for making propellers, an outline pattern having theperipheral contour desired for the propeller, a centering pin uprisingfrom the central portion of said pattern to extend through the center ofthe hub portion of a propeller or propel le'r blank, means carried bysaid pattern for securing said propeller or propeller blank upon saidpin and on said pattern, and an adjustable support carried by andextending upwardly from said pattern to engage and hold each bladeportion of said propeller or propeller blank.

in apparatus for making propellers, an outline pattern having theperipheral contour desired for the propeller, centering pin carried byand uprising from the central portion of said pattern to engage andcenter the hub portion of a propeller or propeller blank, a sleevesurrounding said pin and adapted to engage the bore of the hub portionof said propeller or propeller blank, means carried by said pattern forsecuring said propeller or propeller blank in position upon said sleeveand on said pattern, an adjustable support carried by and extendingupwardly from said pattern to engage and hold each blade portion of saidpropeller or propeller blank, and a cutter member adapted to trim theedges of the propeller blank, said cutter being rotatabl mounted on anaxis parallel to the bore of said propeller blank.

l. in apparatus for making propellers, an outline pattern having thecontour desired for the propeller, means for centering a propeller orpropeller blank upon said pat tern comprising a shaft adapted to extendthrough a central. hole in the hub portion of the propeller blank andhaving fastening means for clamping said propeller blank on saidpattern, and an adjustable support extending upwardly from said patternand having means for engaging and holding the blade portion of the workat the proper height above said pattern.

5. ln apparatus for making propellers, an outline pattern having thecontour desired for the propeller, an adjustable holding support for theblade portion of the work comprising a socket mounted upon said pattern,a split sleeve slidably mounted in said socket and having roughenedengaging means at its upper end, and a locking member having an edgedportion in engagement with the split part of said sleeve and a threadedend for engagement with the work.

6. ln apparatus for making propellers, an outline pattern having thecontour desired for the propeller, an adjustable holding sup port forthe blade portion of the work comprising a socket mounted upon saidpattern, a split sleeve mounted in said socket and having a conicalinner surface at the split portion, and a locking member having aconical surface engaging said conical portion of the sleeve and ascrew-threaded upper end for engagement with the work, and means forturning said locking member to draw the sleeve into engagement with thewdrk and to lock said sleeve in said socket.

In testimony whereof I have hereunto set my hand.

SPENCER HEATH.

